Back rest for chairs



Sept. 16, 1952 J. s. BURDICK BACK REST FOR CHAIRS Filed Sept. 26, 1950 2SllEETS-SHEET 1 Sept. 16, 1952 J. 5. BURDICK BACK REST FOR CHAIRS 2SHEETSSHEET 2 Filed Sept. 26, 1950 Patented Sept. 16, 1952 J as umraozsSfT-ATEYS PATENT OFFICE gj .v V 1 7 :Q v a BA CK RIEST FORCHAIRS I IJanis: Burdi ck; N 015th Muskegon; Mi'ch.,:assignor ,tofTh'e LShawWalkerCompany, Muske'g'on,

I 'ltflich'g'a'corporation of'Michigan aApplication September 26, 1950',tSerialrNo=.;186,'8'1-2 1 Y This invention relates to improvements 1 inchairs, and more particularly to the back rest or back splat portion ofchairs.

The principal object of the invention is to-provide an improved form ofback rest or back'splat unit adapted for chairs having a generallyupright back frame in which the lower edge-of the back rest is spaced afew inches above'the level of the rear edge of 'the seat and is flaredrearwardly of said seatso as to afford maximum comfort in and below thelumbarregion of an average person occupying the chair.

"As heretofore constructed L in conventional backrest designflit' hasbeen customary to provide a plurality of back isplats extending'down-Wardly fromthe toprail of theb'a'ck 'fraine toja horizontal crossbar,with 'thebacksplats curved in a vertical plane toward the -front'of thesplat unitand with the cross .bar curved toward the rear of the unit."The crossbar hasbeen placed at various'levels above the .seat of thechairjbut it'has been customary to formthe cross bar'v'v'ith asubstantially uniform cross section throughout its length and with itsfrontface disposedin substaiitially the same uprightangle as the siderails of the'backframe to which'the opposite 'ends'o'f said crossbar areconnected. Since in most'chair designs the side frame of the backrestisusually slanted slightly toward the rear,lthe ffro nt face of thecross bar usually assumes substantially the same upward and rearwardslant throughout the entire length of the cross bar. As' a result, thecross bar presents a relatively sharp lower edge which is uncomfortableto the occupant.

In carrying out my-invention l provide an improved form of back restunitincluding a back rest area curved in vertical planes toward thefront thereof and terminating'in' a cross bar of substantially uniformcross sectional area curved rearwardly between the side rails of theback frame, wherein said cross bar is of novel form consisting of endportions'having front and rear surfaces substantially in verticalalignment with the side rails of thebackIfrania-but with s'aid surfacesassuming a reversed slanting direction across the center of the'bar fora major'portion of its length, so 'thatsaid crossbar forms arearwardlyfi'aring' "continuation of the convexback rest area of theback splat unit.

The invention may best be understood by reference to the accompanyingdrawings, in which like numerals apply to like parts in each of thefigures:

Figure 1 is a front view of a chair constructed in accordance with myinvention;

. 2 v Figure 2is a top plan view of the'chairshofwn in Figure 1; t

Figure 3 is a side view of thechair; t Figure 4 is a fragme 'tary sideview ofthe chair shown in the foregoing figures with "thelo wer portionpof the back splat unit showninrsection, and indicating thenormalrelation of the back splat unit to the back of an average occupant ofthe chair; I r

Figure 5 an enlarged detailed perspective sectional view of theback railtaken on.line15 5 ofFigurel; t v Figure fi is an enlarged detailed top'plan view of the novel form ofjcross bar forming partoi my invention; pFigure 7 is .a .front view oflthe bar shown in Figure 6; I Figure 8 isFigure 6;

Figure 9iis a Figure 6.

Referringnow-to the details of the 'enibodi: merit of my inventionillustrateddn the draw ings,.the chairshown in Figures 1 to4,vin'clusive, for illustrative purposes is an arm ,chairJof "the typecommonly employed in business oiiices, including as its principalelements abackfframe l0; aseat H, front'legs l2, I2,.rearlegs'jl3,"l3andarrn rests l4, M. The back frameincludes upright side rails l6, l6'filledinby a "back splat unit indicated generally at l'l,"having aplurality of upright splats l8 secured at their upper ends to the toprail 15 and at their lowerendsto a crossbar l9. I The partsihereinabovedescribed maybe made of wood, tubular metal or anyjlike material, ,or' acombination of both wood and metaLalthou'gh it is usually preferablethat the'backsplatiuni't.

an end view of thebar 'shovsin inf bottom: view or the trail shownj irithe seat and thefarm rests be made of wood or other .non' metallicmaterial, in order "to avoid bodily discomfort of the occupant bycontactcwith metal parts which tend to give a chilling'isfensation atrelatively low temperatures. v "Referring now to details. of theformandcon-g struction of the'ba ck splat unit [1, we splats [8 are curvedin a vertical plane toward the front of the' chain'the degree ofcurveiincreasing' in abruptness as'the splates approach'th'e cross bar19, to form a back rest area conforming generally to the shape of theaverage occupants back at the lumbar region, when the occupant issitting in a generally upright position, as indicated in Fig. 4. Saidcross bar is disposed substantially above the top level of the seat I Iin the form shown herein this vertical distance being approximatelythree V 3 or four inches. Although this distance may vary somewhat, thecross bar is preferably spaced vertically above the level of the seat tobe substantially across the sacroiliac region of the average occupantand above the coccyx when the occupant is in a generally upright seatedposition, as shown.

Referring now in greater detail to the novel shape of the cross bar [9as shown in Figures 6 to 9 inclusive, the opposite end faces 20, 20 of Isaid bar are formed in the shape of a substantially equal sidedparallelogram excepting that the front upright face 2| may be slightlyshorter than the rear face 22 of the bar adjacent its opposite ends. Thefront and rear faces meet-the end face 20 at each end of the bar alongupwardly and rearwardly inclined edges 23 and 24,'which aresubstantially parallel with the side rail l6 of the back frame, but thefront and rear faces quickly assume a reversely inclined position asthey progress toward the center of the cross bar so that the majorportion of said cross bar has a front face portion 26 and a rear faceportion 21 both inclined downwardly and rearwardly with respect to thelongitudinal axis of said cross bar, with the greatest degree ofrearward flare along the center of said bar. The upper face of the crossbar remains at a slight forward slant throughout the length of the bar,which is substantially normal to the splats which are secured thereto.The bottom face 29 remains in a substantially hori- Zontal plane, asshown in Figures to 9.

The cross bar [9 can be readily shaped in the special form shown anddescribed in any conventional shaping machine.

The forwardly curved back splats l8 have their lower ends suitablysecured as by mortise and tenon connections 30, 3| along the top of thecross bar so that the front faces of said back splats at their lowerrearwardly curved ends are disposed closely adjacent the rearwardlyflaring central front face portion 26 of the cross bar, so that thelatter bar form a substantial continuation'of said convex rearwardlyflaring back rest area, terminating substantially above andto the rearof the seat I I.

With my novel form of cross bar I9 having its front and rear surfacestapered to conform generally with the lines of the side rails [6 butwith these surfaceschanged in a direction toward and along the majorportion of the bar, substantially in line with the curvature of the backsplats, ample clearance is provided at the height of the cross bar aboveand rearwardly of the seat so as'to relieve any discomforting pressureon the lower part of thespine of an occupant when normally seated inupright position in the chair. In particular it will be noted that, whenthe occupant sits well backward in the seat, the rearwardly anddownwardly flared portion of the back rest gives positive support to thelower lumbar and sacroiliac region tending to induce the occupant toassume the ideal erect seated position with the spine arched naturallyin the lumbar and sacroiliac region.

Accordingly, this novel form of back splat unit therefore combinesmaximum comfort to the user, with a particularly pleasing and effectivestreamlining effect and a maximum strength and minimum amount ofmaterial required for the cross bar [9.

Although I have shown and described a certain embodiment of myinvention, it will be understood that I do not wish to be limited to theexact construction shown and described, but that various changes andmodifications may be made without department from the spirit and scopeof the invention as defined in the appended claims.

It will be further understood that, although my invention has been shownand described in connection with a back rest formed of back splats, thenovel form of cross bar shown and described can equally well beemployedwith other types of back rest means, such as wood, metal, plastic orupholstered back rest units, if desired.

I claim:

1. In a chair, a back frame and seat, the back frame comprising a toprail and side rails connected to the seat and a back splat assemblycomprising a generally horizontal rearwardly curved cross bar having itsopposite ends connected to the side rails so as to extend substantiallyacross the sacroiliac region and above the coccyx of an average occupantof the seat, and a plurality of spaced upright splats extending betweenand fixed to said cross bar and top rail, said back splats being curvedin a vertical plane to present a downwardly and rearwardly flaring backrest areaalong its lower margin, the opposite ends of said cross barbeing joined to the side rails with its front and rear surfaces insubstantial parallel upright alignment therewith, but the plane of thefront face of said cross bar being gradually twisted intermediate itsends to present a downwardly and rearwardly flared surface along itscentral portion at angles corresponding substantially to the adjacentportions of said downwardly and rearwardly flaring back rest portions,and said cross bar being of substantially uniform cross-sectional areathroughout its length.

2. A chair structure in accordance with claim 1, wherein the rearsurface of said cross bar is substantially parallel with the frontsurface thereof throughout the length of said cross bar.

3. A chair structure in accordance with claim 2, wherein the uppersurface of said bar is disposed at a forward slant throughout its lengthsubstantially normal to the splats which are secured thereto.

JOHN S. BURDICK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS O'Connor Dec. 5, 1944

